<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>基本选择器</title>

    <style>
        /*元素选择器*/
        div{
            color: red;
            font-size: 50px;
        }
        /*类选择器*/
        .cls{
            color: blue;
        }
        /*id选择器*/
        #id1{
            color: green;
        }
    </style>
</head>
<body>
    <div>div1</div>
    <div class="cls">div2</div>
    <div class="cls">div3</div>
    <div id="id1">div4</div>
    <div>div5</div>
</body>
</html>